Projection board for enlarging machines



' July 14, 1931.

J. H. JOHNSON PROJECTION BOARD FOR ENLARGING MACHINES Filed July 2, 1928 2 Sheets-Sheet l 1 I N V E N TOR.

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I July 14, 1931. ,1. H. JOHNSON I 1,314,390

PROJECTION BOARD FOR ENLARGING MACHINES Filed July 2, 1928. 2 Sheets-Sheet 2 fig fi INVEN TOR. Jasss florr Jay/x90 If TTORNEY.

Patented July 14, 1931 JESSE HOYT JOHNSON, OF DENVER, COLORADO PROJECTION BOARD FOR ENLARGING MACHINES Application filed July 2, 1928. Serial No. 289,960.

This invention relates to a projection board for enlarging machines more particularly of the type used in commercial plants for enlarging maps, drawings, and the like. It is,

however, not limited to these uses but will be found valuable for any use Where it is desired to throw an enlarged image upon sensitized paper.

The principal object of the invention is to provide a board which will have guides for aligning and cutting the paper and to so arrange these guides that they will separate uniformly from each other so as to outline an area in the exact center of the board at all times.

Another object of the invention is to provide means for carrying the sensitized paper directly upon the board so that it can be withdrawn as required for use.

Still another object is to arrange the paper carrying means so that it can be adjusted to align the paper in the exact center of the board.

A further object is to provide a novel clamping means for the paper so that it can be quickly and efficiently clamped in position.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efficiency. These will become more apparent from the following description.

In the following detailed description of the invention reference is bad to the accompanying drawings which forms a part hereof.

Like numerals refer to like parts in all views tudinal section through the paper container, taken on the line 66, Fig. 2.

Fig. 7 is a fragmentary rear elevation of the projection board illustrating the supporting frame.

Fig. 8 is a detail view illustrating the type of paper clamp employed on the lower guide.

In the drawings the numeral 10 designates the projection board proper, which is supported on cross pieces 11 from a horizontal shaft 12. The shaft 12 is carried in bearlugs on a frame 13 pivoted at 14 to a supporting framework 15. The supporting frame work 15 may be secured to the extremities of tracks 16 upon which the enlarging camera travels.

The shaft 12 and the pivot 14 provide a universal adjustment for the angularity of the board. By rotating it on the shaft 12, it can be brought to an absolutely perpendicular position and locked in place by means of a bolt 17. By means of the pivot 14 it can be swung in a horizontal plane to bring it to a perfect focus field for the enlarging camera. After adjustment has once been made the pivot 14 can be tightened to securely maintain the board in place thereafter.

The shaft 12 can be used to swing the board to the horizontal position, as indicated at A, Fig. 2, should it be desired to work upon its surface. This also serves to lower a container 18 for the sensitized-paper, which is carried on the upper edge of the board, so that the container can be readily reached for replenishing or replacing the paper roll.

An upper guide member 19 and a lower guide member 20 extend entirely across the forward face of the board. These guide members are secured to and supported from an endless cord or cable 21 which passes around upper pulleys 22 at the upper corners of the board and lower pulleys 23 at the lower corners of the board. The uppermember 19 is secured to the forward reach of the endless cord as indicated at 24, Fig. 4, and the lower guide member 20 is secured to the rearward reach of the cord 21 as indicated at 25, in Fig. 5.

By this arrangement, as the lower guide member 20 is pulled downwardly it will travel in a perfectly horizontal position and simultaneously elevate the upper guide member 19 a similar distance so that the two guide members will always be an equal disv tance above and below the horizontal center line of the board. A scale 26 is provided on lower guide member and-can be moved to any desired position along this rod. To prevent the clips 29 from forcing the lower guide member 20 away from the board, I provide a thin apron strip 31 along the upper edge of the lower guide member, against Which, the spring clips clamp the paper.

After the exposure has been made a knife, is run along the lower edge of the eccentric roller 28 in a'groove32 provided in the upper guide member 19 for its reception. This knife separates the exposed paper from the unexposed remainder of the roll and allows the enlargement to be drawn from under the spring clips 29 and taken to the developing trays. The paper 27 can then be drawn down for the second enlargement.-

It will be seen that unusual speed can be obtained with'the use of this device,.si'nc'e all thumb tacks and similar clamping devices have been eliminated. The operator needs only to draw the spring clips 29 backwardly to clamp the lower edge of the paper.. The spring clips 29 are provided withfinger holds 34 by means of which they maybe readily drawn away from the apron '31 for the insertion of paper.

'It is not necessary, as a rule,to clamp the paper at the upper guide. But should it be desired to clamp the paper at this point, the eccentric roller 28 can be rotated by means of a handle 33 so that it will clamp the paper against the upper guide 19. V

It is desired to call particular attentionto the construction of the sensitized paper container 18 which is one of the principal features of this invention. The paper container 18 is secured to the top of the board 10 by means of straps '35 and comprises a cylindrical box or can, closed at its one extremitybv a fixed head 36 and at its other extremity by removable head 37. A slot or channel 38 extends the entire length of the container 18 and opens downwardly over the forward face of the board 10.

In the channel 38 two shafts 39 and 40 are arranged carrying traction rollers 41 and 42. I

The shaft 40 is eccentrically mounted and can be rotated by means of'a head 43 to clamp the roller 42 against the paper. It can be locked in either the clamped or unclamped position by means of a nut 44. The shaft'41 is provided with a crank 45, the rotation of which serves to withdraw the paper from'the container 18.

A slide 46, operated from a handle 47, is employed to completely close the channel 38 when not in use so as to prevent any light from entering the container and exposing the sensitized paper. The sensitized paper is carried on a tube 48 which is clamped between two cones 49 which are in turn secured to a shaft '50 by means ofsuitahle set scre sh shaft 50 extends beyond both extremities of the container 18 and is carried in sleeve; 51 which are slidable Within bushings 52 secured on the container A crank 55 is provided onthe shaft 50 by means of. which the paper can be rewound on its roll when necessary.

traction rollers41 and 42.

The paper passes from its roll over.- an idle roller 54 an position between the Thus, after the paper has been placed in the container the sleeves 5.1 can be forced against the cones 49 and the entire supporting' mechanism is slid withinthe bushings 52 to the right or left until the paper 27 is brought to the exact middle of the board 10.

It is then looked in this position by means of 7 area to be exposed will always be in the proper position without further adjustment.

While a specific form of the improvement has been described and i llustrated herein, it

is desired to be understood that the same may be varied, within the scope of the appended claims,without departing from the spirit of the invention.

Havingthus described the invention, what I claim and'desire secured by Letters Patent is L'Means for aligning and holding sensitized paper upon a projection board for en-' larging machines comprising: an endless cord trained along two side's'of said board and extending across the same; an upper guide member supported by one side of said cord; at lower guide member supported by the other side of said cord; an eccentric roller carried by said upper guidemember and arranged when in one position to clamp .said

paper to said memberpa lower guide member extending across said 'boardsupported by the other side of said cord; a shaft ext-ending along and secured to said lower guide member; and spring clips slidable along said shaft and arranged to engage said paper.

2. Means for clamping sensitized paper to a guide member for projection boards comprising: an apron carried by and extending from said guide member and adapted to pass under said paper; and spring clips supported from said guide member and extending over said apron so as to clamp one edge of said paper against said apron.

3. Means for holding a roll of sensitized paper adjacent an enlarging board comprising: a housing secured to said board; a removable head in one extremity of said housing; a fixed head in the other extremity of said housing; a shaft adapted to pass through said heads; cones arranged to engage the extremities of said roll; means for securing said cones to said shaft; and means for varying the longitudinal position of said shaft within said housing.

4. Means for holding a roll of sensitized paper adjacent an enlarging board comprising: a housing secured to said board; a removable head in one extremity of said housing: a fixed head in the other extremity of said housing; a shaft adapted to pass through said heads; cones arranged to engage the extremities of said roll; means for securing said cones to said shaft; sleeves surrounding said shaft where it passes through said heads, said sleeves arranged to engage said cones and be slidable within said heads; and looking means for securing said sleeves in any desired longitudinal position in said heads, so as to allow the longitudinal position of said roll to be changed within said housing, and to allow various widths of paper to be accommodated.

5. In a projection board means for causing a pair of guide members to move uniformly and in opposite directions across the face of said board said means comprising: double pulleys at two corners of said board; single pulleys at the remaining two corners thereof; a single endless cord extending from one of said single pulleys around three edges of said board over said double pulleys to the other single pulley; and means for attaching the extremities of said guide members to oppositely moving reaches of said cord.

6. Means for attaching photographic paper to a guide member on a projection board comprising: a shaft extending parallel with and carried by said guide member; an apron extending outwardly from one edge of said guide member; a resilient wire coiled about said shaft for a portion of its length and arranged to expand so as to clamp said wire against said apron at one side of said shaft and against said guide member at the other side thereof.

7. Means for attaching photographic paper to a guide memberon a projection board comprising: a shaft extending parallel with JESSE HOYT JOHNSON. 

